Dead bolt latch

ABSTRACT

A dead bolt latch for a door has a cam action for extending the bolt, the cam having the form of a pivoted arm and rotated by the tail piece of lock device. The pivot axis is near one edge of a lock case extension and engages a cam opening in an actuating slide at the opposite side of the case extension. The actuating slide is attached to a latch bolt and shifts the latch bolt between extended and retracted positions when the cam is rotated.

United States Patent 11 1 Sanders et a]. 1 Feb. 5, 1974 DEAD BOLT LATCH 1,007,447 10/1911 Jadronja 70 134 1751 vernard Sanders, hos Angela, 1112222; 51135? 21233111?" ...........::::3.. ?3l?? (5311i; a h 2,042,021 5/1936 Schlage 70 134 ancouver, ana a [73] Assignee: 2031s Industries, Inc., Los Angeles, primary Examiner A1bert Craig [22] Filed: Feb. 7, 1972 ABSTRACT [21] Appl. No.: 224,056 1 A dead bolt latch for a door has a cam action for extending the bolt, the cam having the form of a pivoted C(il. 292/ 1400259c2/33; arm and rotated by the tail piece of lock device The [58] Fie'ld 292/140 pivot axis is near one edge of a lock case extension 292/143 l5 1 DIG and engages a cam opening in an actuating slide at the 6 337 opposite side of the case extension. The actuating slide is attached to a latch bolt and shifts the latch bolt [56] References Cited between extended and retracted positions when the cam is rotated. UNITED STATES PATENTS 528,892 11/1894 Robert 292/ 140 10 Claims, 7 Drawing Figures PATENTED FEB 5I974 SHEU 3 BF 3 DEAD BOLT LATCH The invention relates generally to door locks and particularly to a type commonly termed an auxiliary lock. Of this type are those known as bore-in cylinder deadlocks which consist of a dead bolt latch unit mounted within an edge bore of a door and these are normally operated by means of a key actuated cylinder assembly from the outside of the door and by a turn knob or second key actuated cylinder assembly from the inside. Operating devices as described are normally attached to the door by providing a cross bore which intersects the edge bore allowing the parts to intermember and operatively couple the operating device with the dead bolt latch. The present invention encompasses the dead bolt latch portion of this type of auxiliary lock and particularly one having a bolt projection of as much as l inch in extent.

With an increasing needto provide additional security for doors, it is now a common practice to install within a door, a second or auxiliary lock in addition to one of the more usual forms of locksets, the second lock being commonly termed a dead bolt. Because dead bolts having the customary limited projection of one-half to five-eighths are not sufficient to prevent disengagement by forcing the adjacent door frame laterally with an appropriate tool, dead bolts which provide a longer minimum projection of as much as one inch become advisable. Approved dead bolts may be additionally equipped with a hardened insert within the bolt itself to repel cutting tool attack.

When a door is hung there is invariably a gap between the door edge and its adjacent frame. This circumstance taken in combination with the flexibility of certain types of construction, make a longer dead bolt throw necessary.

The present invention, therefore, encompasses improvements for a dead bolt latch which offer the desirable characteristics required for additional security.

A once inch projection dead bolt latch made possible by the present invention complies with all of the customary requirements and yet maintains an overall size that is in keeping with prior existing products having lesser projection and security. Such construction provides a unit which can replace existing installations and at the same time provide increased security.

The structure of the present invention makes use of improvements which provide the required strength and ease of operation over a long life span yet are such that all of the components may be created by low cost high production means which are easily assembled into the complete dead bolt latch. This approach to low cost manufacture without sacrifice of quality is a primary consideration in view of keen competition currently existing within the builders hardware industry. The present structure is, therefore, designed to be fabricated predominently from low-cost metal stampings and turned parts.

Among the objects of the invention is therefore to provide a new and improved dead bolt latch having a projection oflength exceeding previous capabilities but which can be installed in a bore of the same dimensions as those already in use.

Another object of the invention is to create the necessary components of a dead bolt latch mechanism by low-cost means, the components being adapted to be easily assembled into a complete latch.

A further object is provide a new and improved dead bolt latch capable of utilizing a minimum number of components and which will provide the required function without sacrifice of strength, life or ease of operation.

An additional object of the invention is to provide a new and improved dead bolt latch which incorporates a positive blocking means capable of deadlocking the bolt when projected, to prevent unauthorized manipulation.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a longitudinal cross-section view of the dead bolt latch and its operating device in place on a door.

FIG. 2 is a longitudinal sectional view on the line 2 2 of FIG. 1 with the dead bolt retracted.

FIG. 3 is a longitudinal sectional view similar to FIG. 2 with the dead bolt extended.

FIG. 4 is a cross-sectional view taken along the line 4 4 of FIG. 3.

FIG. 5 is a cross sectional view taken on the line 5 5 of FIG. 3.

FIG. 6 is a cross sectional view taken on the line 6 6 of FIG. 2.

FIG. 7 is an exploded view of the separate parts of the dead bolt mechanism.

In an embodiment of the invention chosen for the purpose of illustration as shown in FIGS. 1 and 2, a dead bolt latch mechanism is indicated generally by the reference character l0, mounted in an appropriate edge bore ll ofa door 112. The latch 10 has a face 13 which provides means for fastening the latch 10 to an edge 14 of the door l2 by use of the screws 15. The face 13 has a central opening 16 through which the bolt head 17 may be projected for cooperative engagement within an opening iii of the strike plate l9 which is mounted in properly aligned relationship with the latch 10 and secured to a frame 20 by means of the screws 21. Behind the strike plate 19 is shown a strike box 22 which serves to neatly trim the required cutout in the frame 20 and also assures that the cutout provides a hole 23 of sufficient depth to accornodate the bolt 17 when in a fully extended position.

A cross bore 25 between outer and inner faces 12 and 12" of the door 12 provides for attachment of appropriate actuating means for the latch 10 such for example as a key operated cylinder assembly 26 on the outer face 12 and a turn knob assembly 27 on the inner face 12".

The edge bore 11 in which latch mechanism 10 is mounted is perpendicular to the edge 14 of the door 12 and the outer and inner actuating; means 26 and 27 intermember and operatively couple with the latch mechanism 10.

The cylinder assembly 26 is substantially conventional and includes an outer shell 30 crimped to a mounting plate 31 and adapted to retain a pin tumbler mechanism 32 by means of the clip 33. Affixed to the mounting plate 31 is a pair of internally threaded mounting posts 34, 35 which intermember a portion of the latch 10 by means of appopriate spaced openings 36, 37 therein which properly align and prevent rotation of the cylinder assembly 26.

The pin tumbler mechanism 32 is of conventional construction having a plug 38 that is rotatable by the agency of a proper key (not shown). At the inner end of the plug 38 is tailpiece 43. A lost motion type of action is employed to allow the key to be returned to a normal or key out position after actuating the dead bolt mechanism 10.

The turn knob assembly 27 has a rose 40 adapted to rotatably retain a turn knob 41 whose inner end is configured with an opening 42 for telescopically receiving the tailpiece 43 in operative engagement. The previously mentioned lost motion coupling allows the turn knob 41 to actuate the latch bolt mechanism when the pin tumbler mechanism 32 is in a locked condition. The rose is also provided with mounting screws 44, 45 which threadably engage the mounting posts 34, 35 and securely clamp the cylinder assembly 26 and the turn knob assembly 27 to the outer and inner faces 12, 12" respectively of the door 12.

Referring now to FIG. 7 as well as FIGS. 1 and 2 the latch bolt mechanism 10 has a case with upper and lower front flanges 51 and 52 respectfully, having openings 53 and 54 therein for stakably retaining the face 13 by means of tubular extruded portions 55 and 56. At the rearward end of the case 50 is a series of tabs 57, 58, 59 and 60 between which are end face segments 61, 62, 63 and 64 the purpose of which is to locate and retain a case extension as an elongation of the case 50, as best seen in FIGS. 2 and 3.

The case extension 70 is of a modified box like form and at the end adjacent the case 50 has outwardly formed foreward portions 71, 72 that contain arcuate recesses 73, 74, 75 and 76 etc., for intermemberment with the tabs 57, 58, 59 and 60. Side walls 77, 78 of the extension 70 are maintained in parallel spaced relationship by a forward tab 79 and a rearward tab 80 on which is an extension 81 bent downwardly when in assembled position, to securely tie the side walls 77, 78 together. Adjacent the upper area of the side walls 77, 78 are a pair of outwardly formed guide rails 82, 83 that extend for a portion of the length of the case extension 70. A further outward extending portion 84 of the guide rail 82 provides a stop 85. Aligned openings 86, 87, 88 and 89 are provided in the side walls 77, 78 respectively of the case extension 70 to allow intermemberment of the latch bolt mechanism 10 with the posts 34, 35 of the cylinder assembly 26.

The bolt head 17 has a rearward facing slot 90 for reception of the forward end of an actuator slide 91. The bolt head 17 has also a blind hole 92 opening at the rear into the slot 90, the hole 92 being of a size slightly larger in diameter and length than that of a hardened steel roller 93 which is entrapped in the hole 92 when the actuator slide 91 is intermembered with the bolt 17 and retained by staking portions 94, 95 of the bolt 17 adjacent the slot 90 as viewed in FIGS. 2, 3 and 5. To ensure axial retention of the roller 93, an inwardly formed area 96 is provided on the foreward portion 99 of the actuator slide 91. The slide 91 is formed with a channel like shape having downwardly extending forward portions 98, 99 that intermember the slot 90 of the bolt 17 and contain inwardly directed tabs 100, 101 that abut at a central point to maintain the spacing of the forward portions 98, 99. On the upper surface of the slide 91 near its forward end are openings 102, 103

abd deformed areas 104, 105 for the purpose of anchoring the short leg 106 of a hairpin shaped detent spring 107 (see FIGS. 2 and 3). The rearward portion of the actuator slide 91 contains a cam opening 108 and a pair of outwardly formed guides 109, 1 10 having respective inwardly formed projections 111, 112 that intermember with the guide rails 82, 83 of the case extension 70. I

A cam 115 in the form ofa lever has a circular offset bearing portion 116 that intermembers an opening 117 in the side wall 77 of the case extension 70 and contains a centrally located slot 118 for reception of the tail- .piece 43. The upper area of the cam 115 has a forwardly facing arcuate cam face 119 and a rearwardly facing arcuate cam face 120 for reciprocatably moving the actuator slide 91 by engagement with respective shoulders 126 and 127 at opposite ends of the cam opening 108. The cam 115 also has an end face 121 adjacent the cam faces 119, 120 and a detent lug 122 which is offset in a direction opposite the bearing portion 116 and located approximately halfway between the slot 118 and the cam faces 119, 120. The detent lug 122 is in contact with the lug leg 123 of the detent spring 107.

To properly retain the cam 115 in its bearing opening 117 are provided inward offsets 124 adjacent a clearance hole 125 (see FIG. 1) in the side wall 78 of the case extension 70, the hole 125 being in coaxial alignment with the bearing opening 117.

As represented in FIGS. 2 and 6, the slide 91 rides upon the guide rails 82 and 83 and its rearward end is prevented from any lifting action by the cam 115 as a result of the projections 111, 112 underlying the guide rails 82, 83.

For shifting the bolt head 17 from a retracted position to an extended position or from extended back to retracted position the cam 115 is rotated clockwise, or counter clockwise as the case may be. This is accomplished by rotation of the tailpiece 43 either by a proper key inserted in the pin tumbler mechanism 32, the cylinder assembly 26 or the turn knob 41.

FIGS. 2 and 3 show the mechanism respectively in retracted and extended positions. Action of the detent spring 107 is such that its bias against the detent lug 122 of the cam 115 causes the cam 115 to be biased downward whereby the rearward cam face 120 or the forward cam face 119 is in contact with the rearward shoulder 126 or forward shoulder 127 respectively of the opening 108 of the actuator slide. During the operation the cam lever swings in an opening created by the outwardly formed guide rails 82, 83 of the case extension 70. When in the retracted position of FIG. 2, the bolt head 17 is deadlocked against outward movement by engagement of the rearward face of the bolt head 17 with the foreward portions 71, 72 of the extension 70 and the rear shoulder 126 of the cam opening 108 with the end face 121 of the cam lever 115.

In extended position, as shown in FIG. 3, the bolt head 17 is deadlocked against movement by the guide 109 of the actuator slide 91 being in contact with the stop 85 of the outwardly extending portion 84 of the guide rail 82 on the case extension 70, in cooperation with the foreward shoulder 127 of the cam opening 108 in contact with the end face 121 of the cam 115. Any attempt to dislodge the bolt head is prevented by the force moving through the cam lever and against its bearing because the detent action of the spring 107 will not allow the cam 115 to rotate.

As shown in FIGS. 2 and 3, clockwise and counterclockwise rotation of the cam 115 is stopped respec tively by engagement of the cam with a corner 128 and cam face 119 with a corner 129.

Although the mechanism of the latch mechanism just described offers great resistance to bolt movement in the deadlocked position, its action through normal cam rotation is one of ease and smoothness because the arcuate cam faces 119, 120 have a form which provides a low pressure angle against the shoulders 126 and 127 of the cam opening 108.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A dead bolt latch mechanism for installation in a door and for cooperation with a strike plate when in locked position, said mechanism comprising a tubular case of circular cross-sectional shape adapted for mounting on a door at a free edge thereof, a longitudinal guide means on one side of the longitudinal center line of the case, a cam arm pivotally mounted on a pivot axis of said case on the opposite side of said longitudinal center line, said cam arm having a free end movable between locked and unlocked position, said longitudinal guide means extending horizontally for a distance substantially equal to the distance between locked and unlocked positions of the free end of said cam arm, a bolt assembly comprising a bolt head having a concentric reciprocatable mounting in the case, said bolt assembly having a guide retention means on one side only of the longitudinal center line thereof in sliding engagement with said guide means, and shoulder means at the outermost edge of the bolt assembly adapted to be engaged by the cam arm whereby to effect movement of said bolt assembly between locked and unlocked positions.

2. A dead bolt latch mechanism for installation in a door and for cooperation with a strike plate when in locked position,

said mechanism comprising a tubular case adapted for mounting on a door at a free dge thereof,

a longitudinal case extension at one end of the case,

a longitudinal guide means at one edge of the case extension,

a cam arm pivotally mounted on a transverse pivot axis at the other edge of the case extension,

said cam arm having oppositely facing cam faces at a free end thereof,

a bolt assembly comprising a bolt head reciprocatably mounted in the case and an actuator slide attached to the inside end of the bolt head,

said actuator slide having a guide retention means in sliding engagement with said guide means and shoulder means on the actuator slide adapted to engage respective cam faces on the cam arm whereby to effect movement of said bolt assembly between locked and unlocked positions in response to rotation of the cam arm.

3. A dead bolt latch mechanism as in claim 2 wherein there is a cam shoulder on the cam arm extending in a direction transverse relative to the long dimension of the arm, and a complementary shoulder on the actuator slide having a blocking engagement with the cam shoulder when the bolt assembly is in locked position whereby to secure the bolt assembly in aid locked position.

4. A dead bolt latch mechanism as in claim 3 wherein there is a second complementary shoulder on the actuator slide having a blocking engagement with said cam shoulder when the bolt assembly is in unlocked position.

5. A dead bolt latch mechanism as in claim 2 wherein said longitudinal guide means comprises opposite laterally outwardly extending rails.

6. A dead bolt latch mechanism as in claim 2 wherein said case extension comprises sheet metal plate sections fastened in parallel spaced relation and having a chamber therebetween, said cam arm being located in said chamber.

7. A dead bolt latch mechanism as in claim 2 wherein said actuator slide comprises sheet metal plate sections and a transverse sheet metal section joining said sheet metal plate sections in parallel spaced relation forming a space therebetween exceeding in width the width of said case extension and wherein said guide retention means comprises portions of said sheet metal plate sections slidably embracing said longitudinal guide means.

8. A dead bolt latch mechanism as in claim 2 wherein there is a spring adapted to travel with and having one spring portion in engagement with said actuator slide, a detent on said cam arm in engagement with another portion of said spring whereby said cam arm is releasably biased respectively in locked and unlocked positions of said bolt head.

, 9. A dead bolt latch mechanism as in claim 8 including a spring keeper on said cam arm, said spring comprising a bent wire element having one end in engagement with said actuator slide, the other end of the spring being located within said case extension in a position of sliding engagement with said spring keeper.

10. A dead bolt latch mechanism as in claim 2 wherein there is a longitudinal inwardly open bore in said bolt head, a hardened pin loosely mounted in said bore, and a portion of said actuator slide overlying said bore whereby to retain said pin in said bore. 

1. A dead bolt latch mechanism for installation in a door and for cooperation with a strike plate when in locked position, said mechanism comprising a tubular case of circular cross-sectional shape adapted for mounting on a door at a free edge thereof, a longitudinal guide means on one side of the longitudinal center line of the case, a cam arm pivotally mounted on a pivot axis of said case on the opposite side of said longitudinal center line, said cam arm having a free end movable between locked and unlocked position, said longitudinal guide means extending horizontally for a distance substantially equal to the distance between locked and unlocked positions of the free end of said cam arm, a bolt assembly comprising a bolt head having a concentric reciprocatable mounting in the case, said bolt assembly having a guide retention meanS on one side only of the longitudinal center line thereof in sliding engagement with said guide means, and shoulder means at the outermost edge of the bolt assembly adapted to be engaged by the cam arm whereby to effect movement of said bolt assembly between locked and unlocked positions.
 2. A dead bolt latch mechanism for installation in a door and for cooperation with a strike plate when in locked position, said mechanism comprising a tubular case adapted for mounting on a door at a free dge thereof, a longitudinal case extension at one end of the case, a longitudinal guide means at one edge of the case extension, a cam arm pivotally mounted on a transverse pivot axis at the other edge of the case extension, said cam arm having oppositely facing cam faces at a free end thereof, a bolt assembly comprising a bolt head reciprocatably mounted in the case and an actuator slide attached to the inside end of the bolt head, said actuator slide having a guide retention means in sliding engagement with said guide means and shoulder means on the actuator slide adapted to engage respective cam faces on the cam arm whereby to effect movement of said bolt assembly between locked and unlocked positions in response to rotation of the cam arm.
 3. A dead bolt latch mechanism as in claim 2 wherein there is a cam shoulder on the cam arm extending in a direction transverse relative to the long dimension of the arm, and a complementary shoulder on the actuator slide having a blocking engagement with the cam shoulder when the bolt assembly is in locked position whereby to secure the bolt assembly in aid locked position.
 4. A dead bolt latch mechanism as in claim 3 wherein there is a second complementary shoulder on the actuator slide having a blocking engagement with said cam shoulder when the bolt assembly is in unlocked position.
 5. A dead bolt latch mechanism as in claim 2 wherein said longitudinal guide means comprises opposite laterally outwardly extending rails.
 6. A dead bolt latch mechanism as in claim 2 wherein said case extension comprises sheet metal plate sections fastened in parallel spaced relation and having a chamber therebetween, said cam arm being located in said chamber.
 7. A dead bolt latch mechanism as in claim 2 wherein said actuator slide comprises sheet metal plate sections and a transverse sheet metal section joining said sheet metal plate sections in parallel spaced relation forming a space therebetween exceeding in width the width of said case extension and wherein said guide retention means comprises portions of said sheet metal plate sections slidably embracing said longitudinal guide means.
 8. A dead bolt latch mechanism as in claim 2 wherein there is a spring adapted to travel with and having one spring portion in engagement with said actuator slide, a detent on said cam arm in engagement with another portion of said spring whereby said cam arm is releasably biased respectively in locked and unlocked positions of said bolt head.
 9. A dead bolt latch mechanism as in claim 8 including a spring keeper on said cam arm, said spring comprising a bent wire element having one end in engagement with said actuator slide, the other end of the spring being located within said case extension in a position of sliding engagement with said spring keeper.
 10. A dead bolt latch mechanism as in claim 2 wherein there is a longitudinal inwardly open bore in said bolt head, a hardened pin loosely mounted in said bore, and a portion of said actuator slide overlying said bore whereby to retain said pin in said bore. 